Mercury officially opens Nga Tamariki Unit 5 geothermal power station in New Zealand

Mercury has officially opened the fifth operating unit of the Nga Tamariki geothermal power station near Taupo in New Zealand. This follows up on the previous report of the start of grid supply from the new power plant before the commissioning process had been completed.

The $220 million expansion project was first announced in 2023, with construction beginning in 2024. Completed in just under two years, the project lifts the station’s annual average generation output to about 1120GWh. The Nga Tamariki expansion project was developed with support from Mercury’s commercial partner Tauhara North #2 Trust and with mana whenua Ngati Tahu Ngati Whaoa to ensure the sustainability of the geothermal reservoir and management of the surrounding environment.

Along with the project partners, about 300 contractors and staff who worked on the project over the past years joined the opening ceremony for the new geothermal power station. These included contractors and consultants from Taupo, Rotorua, Hamilton, New Plymouth, Napier and beyond.

Mercury Chief Executive Stew Hamilton stated that, at 55 MW (presumably gross power generation capacity), the new unit has more than twice the capacity of each of the original units commissioned at Nga Tamariki in 2013.

In parallel with the construction of the new power plant, Mercury has also drilled two new geothermal wells – one production well and one reinjection well. Hamilton says that this has helped the site in its campaign to reinject non-condensable gases back into the reservoir, thus contributing to the target of 70% reduction in the station’s carbon emissions by 2030. Nga Tamariki was the first geothermal power station in New Zealand to implement NCG reinjection.

“Geothermal is central to our long-term growth. The expansion at Nga Tamariki will help us deliver 3.5 TWh of new generation by 2030. That’s about 8% of New Zealand’s annual energy demand,” said Hamilton, adding that Mercury is also partnering with the Government of New Zealand’s initiative to investigate supercritical geothermal energy.

Mercury operates the geothermal power station in the Rotokawa region, which has been selected as the site for the first superhot geothermal well to be drilled in New Zealand.

Source: Mercury